/Engine/Plugins/Animation/IKRig/Source/IKRigEditor/Public/RetargetEditor/IKRetargetAnimInstanceProxy.h
Cache bones override point. You should call CacheBones on any nodes that need it here. bBoneCachesInvalidated is used to only perform this when needed (e.g. when a LOD changes), as it is usually an expensive operation.
virtual void CacheBones()